1. MONTE-CARLO TECHNIQUES APPLIED TO PROTON DOSIMETRY AND RADIATION SAFETY F. Guillaume, G. Rucka, J. Hérault, N. Iborra, P. Chauvel 1 XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

2. Proton beam line Treatment room Set-up MEDICYC 65 MeV protons Isochronus cyclotron 2 MEDICYC XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

3. X X Y Y Z Z Range modulating wheel Collimator Bolus Wedge diode Range Shifter Set-up 3 Clinical beam XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

4. Monte-Carlo Present Dosimetric evaluation of Monte-Carlo code on the basis of simulations and measurements Quantification of secondaries (neutrons, photons) Radiation safety evaluation Achieved with MCNPX, in progress with GEANT 4 Long term Integrate Monte-Carlo technique in Treatment Planning Systems Use Monte-Carlo technique for optimizing isotopes production 4 Goal XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

5. Monte-Carlo MCNPX v 2.4.0 (Monte Carlo N-Particle Transport Code) GEANT 4 (GEometry ANd Tracking) Versatility photons, electrons, neutrons, protons, pions… transport DICOM interfaces Fluence Dose, equivalent dose, isotopes production 5 Code choice XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

6. MCNPX BENCHMARK MCNPX OPTICAL BENCH SECTION Monte-Carlo Geometry 6 XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

7. MCNPX –Study performed by Gunther RUCKA –Advantages Good results Easy to use –However Does not follow secondary electrons No time dependence for geometry 7 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

8. GEANT4 –Advantages Geometry can change over time Open package: everything is possible! Follow all particles Wide examples databank –Drawbacks Necessitates a good knowledge in C++ Sometimes confusing Easier to make mistakes 8 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

9. Set up –Computing system Intel Pentium D dual core 3.20 Ghz 2 Go RAM 64 bit system –Linux CentOS 64 bit CLHEP, DAWN (visualization), AIDA... 9 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

10. Geometry Physics –A lot of models available Decay EM interactions Hadronic interactions –Several validation studies have been performed 10 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

11. Geometry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006 11

12. XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006 12

13. Current work –validating GEANT4 simulation for proton dosimetry at the CAL in Nice Biggest issue: computation time Try to optimize the calculation –Powerful computer –Optimizing the efficiency (0.3% to 30%) –Computing time and resources depends on: »geometry »physic models 13 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

14. LATERAL PROFILES + ERREURS NICE Results Lateral Profiles 14 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

15. Results Bragg peaks BRAGG PEAKS NICE 15 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

16. Further work –Simulate the modulating wheel (SOBP) –Import DICOM data and calculate dose deposited within anatomical volumes (TPS) –Need the validation first 16 Validation of Monte Carlo techniques for proton dosimetry XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

17. 17 Validation of Monte Carlo techniques for proton dosimetry Summary –MCNPX provides excellent results –GEANT4 is currently showing encouraging results although the study is still in progress –MCNPX offers easiness of use while GEANT4 is more flexible. Besides GEANT4 necessitates a bigger personal involvement

18. y z Monte-Carlo Additional geometry for radiation safety 18 XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

19. Neutron fluence spectrum (MCNPX) 19 Monte-Carlo XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

20. Origin of secondaries (MCNPX) Optical bench neutrons and photons (without water phantom) Monte-Carlo 20 Optical bench+water neutrons and photons (with water phantom) XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

21. Monte-Carlo 21 Radiation safety application MCNPX (ICRU57) BF3 counter One treatment session (13 Gy) XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

22. Neutron dose (Gy) 13 Gy one eye treatment session 52Gy eye treatment 22 Radiation safety application (MCNPX) Monte-Carlo XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006

23. Monte-Carlo technique is an interesting tool for dosimetry and radiation safety in hadrontherapy. However, a particular attention must be focused on physics modeling as preamble (cross-section, nuclear models, stopping power, energy straggling, multiple Coulomb scattering…) for obtaining accurate results. These codes are useful for routine in hadrontherapy: Dose per monitor unit (cGy/MU) for clinical treatment are verified using MCNPX. For CAL beam line, neutron contributions are insignificant dosimetrically speaking. XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006 23 Conclusion

24. –MCNPX http://mcnpx.lanl.gov/ –GEANT4 http://geant4.web.cern.ch/geant4/ 24 Thank you for your attention! XXXV European Cyclotron Progress Meeting, Nice, November 2-4, 2006